Development and Investigation of Thermal Devices on Fully Porous Silicon Substrates

For thermal sensors and devices, porous silicon is a comparably novel alternative to standard materials such as thin glass substrates or silicon nitride membranes. These materials are primarily characterized by their thermal conductivity and heat capacity, as well as temperature stability and mechanical fragility. In this paper, we present details of the porous silicon technology for full wafer porosification as well as static and dynamic device and material characterization. The reduction of thermal conductivity is estimated with the dynamic 3ω technique and compared with pure silicon and silica glass wafers. Thin film microheaters have been deposited on the samples as proof of concept for the characterization and comparison of thermal insulation, heat capacity, as well as thermal and mechanical stability.